Structure-based design of antiviral drug candidates targeting the SARS-CoV-2 main protease.

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is the etiological agent responsible for the global COVID-19 (coronavirus disease 2019) outbreak. The main protease of SARS-CoV-2, Mpro, is a key enzyme that plays a pivotal role in mediating viral replication and transcription. We designed and synthesized two lead compounds (11a and 11b) targeting Mpro Both exhibited excellent inhibitory activity and potent anti-SARS-CoV-2 infection activity. The x-ray crystal structures of SARS-CoV-2 Mpro in complex with 11a or 11b, both determined at a resolution of 1.5 angstroms, showed that the aldehyde groups of 11a and 11b are covalently bound to cysteine 145 of Mpro Both compounds showed good pharmacokinetic properties in vivo, and 11a also exhibited low toxicity, which suggests that these compounds are promising drug candidates.

Cellulose derived nitrogen and phosphorus co-doped carbon-based catalysts for catalytic reduction of p-nitrophenol.

The cellulose, which is one of the most abundant solid by-products of agriculture and forestry industry, has been successfully tested for the synthesis of nitrogen and phosphorus co-doped carbon-based metal-free catalysts (NPC) via freeze-drying the mixture of cellulose crystallite and ammonium phosphate, followed by annealing of the hydrogel under nitrogen atmosphere at 800 °C for 2 h. Different techniques including TEM, SEM, FTIR and XPS spectroscopy have been applied to characterize the as-prepared NPC, which presents flake-like morphology with N and P doping levels of 4.3 atom% and 10.66 atom%, respectively. The NPC exhibits excellent catalytic activity for the reduction of p-nitrophenol (p-NP). The turnover frequency (TOF) of the reduction of p-NP is as high as 2 × 10-5 mmol·mg-1·min-1 and the apparent kinetic rate constant was calculated as 0.0394 min-1 at room temperature. The catalytic mechanism is proposed by combining the density functional theory calculation and analysis of the experimental results. These findings open up new possibilities of valorization for cellulose-based by-product and treatment of p-NP-based wastewater.

ABHD5 blunts the sensitivity of colorectal cancer to fluorouracil via promoting autophagic uracil yield.

The efficacy of Fluorouracil (FU) in the treatment of colorectal cancer (CRC) is greatly limited by drug resistance. Autophagy has been implicated in chemoresistance, but the role of selective autophagic degradation in regulating chemoresistance remains unknown. In this study, we revealed a critical role of ABHD5 in charging CRC sensitivity to FU via regulating autophagic uracil yield. We demonstrated that ABHD5 localizes to lysosome and interacts with PDIA5 to prevent PDIA5 from interacting with RNASET2 and inactivating RNASET2. ABHD5 deficiency releases PDIA5 to directly interact with RNASET2 and leave RNASET2 in an inactivate state, which impairs RNASET2-mediated autophagic uracil yield and promotes CRC cells to uptake FU as an exogenous uracil, thus increasing their sensitivity to FU. Our findings for the first time reveal a novel role of ABHD5 in regulating lysosome function, highlighting the significance of ABHD5 as a compelling biomarker predicting the sensitivity of CRCs to FU-based chemotherapy.

[Research on XOD captured components in Lagotis brevituba based on UPLC-Q-TOF-MS and molecular docking technology].

Potential xanthine oxidase (XOD) inhibitors in Lagotis brevituba were captured by using affinity and ultrafiltration. The structures of the captured components were identified by ultra-performance liquid chromatography coupled with Q-TOF mass spectrometry (UPLC-Q-TOF-MS). The binding intensity and binding mechanism between the captured components and XOD were analyzed by using molecular docking software Autodock 4.2. A total of 17 compounds were identified, including 9 flavonoids, 5 phenolic acids and 3 triterpenes. Molecular docking results showed that all the captured components could be spontaneously bound with XOD mainly via hydrogen bond, Van der Waals' force and hydrophobic interaction. From the perspective of binding energy and scoring function, the collected fractions all had potential prospects for XOD inhibitors, and the flavonoid luteolin-3',7 glucuronide had the best effect. The results also showed that affinity and ultrafiltration, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and molecular docking technology can provide a powerful tool for the analysis of XOD inhibitor components in natural products.

Berberine Derivatives with Different Pharmacological Activities via Structural Modifications.

Berberine, a quaternary ammonium protoberberine alkaloid with an isoquinoline scaffold isolated from medicinal herbs, exhibits a wide spectrum of pharmacological activities. Berberine has been used in traditional Chinese medicine and Ayurvedic medicine. However, it has poor bioavailability, which seriously limits its application and development. The chemical transformation of natural products is an effective method to improve pharmacological activities. Researches have been carried out on the modification of berberine to obtain better pharmacological properties. In this paper, the structural modifications of berberine for different biological activities and its underlying mechanisms are reviewed.

Molecular Mechanisms Underlying the Inhibitory Effects of Qingzaojiufei Decoction on Tumor Growth in Lewis Lung Carcinoma.

OBJECTIVE: Qingzaojiufei decoction (QD) is an empirical herbal formula from traditional Chinese medicine that is used for the treatment of lung-related diseases. However, the effect of QD on the growth of lung tumor cells has not been investigated. The aim of this study was to examine the antitumor activity of QD in Lewis lung carcinomas (LLC) in vivo and in vitro, and to elucidate the underlying mechanisms. METHODS: The LLC cells were used to assess the antitumor activity of QD by Cell Counting Kit-8 assay in vitro. In vivo, mice were randomly assigned to 5 groups (n = 10/group): the model control (MC) group was intragastrically administered physiological saline (0.9% NaCl) twice daily from day 2 after tumor implantation for 2 weeks. The QD groups were intragastrically administered QD twice daily from 2 weeks before to 2 weeks after tumor implantation for 4 weeks. The mRNA levels were detected by quantitative polymerase chain reaction, the proteins expression was determined by immunohistochemistry or western blotting. RESULTS: Compared with the model group, QD showed inhibition of proliferation of LLC cells and reductions in tumor weight and proliferating cell nuclear antigen protein expression. Furthermore, QD up-regulated p53 mRNA expression, and downregulated c-myc and Bcl-2 mRNA expression, while MMP-9, VEGF, and VEGFR protein expression was suppressed. Phosphorylated ERK1/2 levels were also reduced by QD in a dose-dependent manner. CONCLUSION: Our findings suggest that QD inhibited lung tumor growth and proliferation, by activation of tumor suppressor genes, inactivation of oncogenes, suppressing the potential for invasion and metastasis, and attenuating angiogenesis. The ERK/VEGF/MMPs signaling pathways may play an important role in QD-induced inhibition of malignant tumor cell proliferation.

[Fast identification of constituents of Lagotis brevituba by using UPLC-Q-TOF-MS/MS method].

The chemical constituents of Lagotis brevituba were rapidly determined and analyzed by using ultra performance liquid chromatography tandem quadrupole time of flight mass spectrometry (UPLC-Q-TOF-MS/MS) method, providing material basis for the clinical application of L. brevituba. The separation was performed on UPLC YMC-Triart C18 (2.1 mm×100 mm, 1.9 µm) column, with acetonitrile-water containing 0.2% formic acid as mobile phase for gradient elution. The flow rate was 0.4 mL•min-1 gradient elution and column temperature was 40 ℃, the injection volume was 2 µL. ESI ion source was used to ensure the data collected in a negative ion mode. The chemical components of L. brevituba were identified through retention time, exact relative molecular mass, cleavage fragments of MS/MS and reported data. The results showed that a total of 22 compounds were identified, including 11 flavones, 6 phenylethanoid glycosides, 1 iridoid glucosides, and 4 organic acid. The UPLC-Q-TOF-MS/MS method could fast identify the chemical components of L. brevituba, providing valuable information about L. brevituba for its clinical application.

[Effect of simvastatin on the reserve of heart function and endothelial function in X-syndrome].

OBJECTIVE: To determine the therapeutic effect of simvastatin combined with traditional medicine on patients with X-syndrome, and on the reserve of heart function and endothelial function. METHODS: Forty patients with X-syndrome were recruited from September 2006 to September 2007 and randomly divided into 2 groups (a simvastatin group and a control group). The control group received routine treatment including beta receptor blocker, calcium-channel blocker (CCB) and long active nitrate. The simvastatin group received simvastatin and the routine treatment. The clinical condition and exercise test (TET) were performed before and after the treatment.The levels of triglyeride (TG), total cholesterol (TC), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C), endothelin-1 (ET-1) and nitric oxide (NO) were measured. RESULTS: The frequencies of chest pain in the simvastatin group were lower than those in the control group. The levels of ET-1, ET-1/NO, TG, TC, and LDL-C were significantly decreased in the simvastatin group as compared with the control group after the treatment. The levels of HDL-C and NO were significantly increased in the simvastatin group as compared with the control group after the treatment. The time in TET was significantly increased in the simvastatin group as compared with the control group. The frequencies of chest pain were positively related to the level of ET-1/NO and negatively related to the time in TET. CONCLUSION: Simvastatin is effective for patients with X-syndrome and may improve the endothelial function and the reserve of heart function.

[Effect of BST on synapse protein SYT and SYN in the hippocampus of chronic stress depression in rats].

OBJECTIVE: To explore the effects of Baisong tablets (BST) on synapse protein synatotagmin (SYT) and synaptophysin (SYN) of hippocampus in chronic stress depression in rats. METHODS: Twenty eight male Sprague-Dawley rats were randomly allocated to 4 groups: a normal control group,a model group,a fluoxetine (FXT) group and a BST group. The normal control rats were fed in a natural environment. Rats of the model, FXT and BST groups were singly housed and given an chronic unpredicted sequence of mild stressors. The distribution and expression differences of SYT and SYN in the hippocampus of rats in different groups were investigated with in situ hybridization and immunoblotting. RESULTS: Expressions of SYT and SYN in the hippocampus of model rats were significantly reduced, compared with that of the normal control (P<0.05); and the expressions of SYT and SYN were significantly increased in the hippocampus of the FXT and BST groups, compared with that of the model group (P<0.05). CONCLUSION: The expressions of SYT and SYN protein and their mRNA decrease in the hippocampus of stress-model rats. BST can up-regulate their expression.